Documention URL in the about section is missing

[t-huyeng]

@AndreasFischer1985 could you please add the documentation-URL in the about section:
https://dashboard.deutschland.api.bund.dev

As described in bundesAPI/apis#23, bundesAPI/apis#30 and https://github.com/bundesAPI/terraform/issues/27, if the fork is done by a personal account instead of terraform, only the personal account can change the about section and other settings. So I think we should try to add forks via Terraform for better maintenance. If this is possible.